Steven Fletcher is likely to begin his Sunderland career on the substitutes bench against Reading at the Stadium of Light on Saturday after finally completing a protracted £12m move from Wolves. He has been joined at the club by Adam Johnson, who has completed a £10m move to Wearside.

Fletcher has joined on a four-year contract but, because of an ankle injury, has barely played or trained during pre-season at Molineux and will be eased into Martin O'Neill's team.

"Steven's underrated but not by me," said Sunderland's manager, who will give Fletcher a fitness test before kick-off against Brian McDermott's side. "I think he's capable of scoring goals and linking play which is very important to us. Steven's got a proven track record of scoring goals. He's very good but, at 25, he's got room to improve and really get better. It's vital we got him."

Speaking of Johnson, O'Neill added: "Adding quality players to the squad has been our main aim this summer and Adam certainly fits that bill. He has terrific ability, great delivery and I'm sure he is a player who will excite our fans.

"I couldn't be more delighted to have him at the football club."

O'Neill is continuing to pursue deals, including the striker John Guidetti on loan from Manchester City, as he strives to infuse his side with some much needed pace and trickery which would also make Sunderland more effective on the counter-attack.

"I'm still trying to improve the team," he said. "We need some more help and we're trying to provide that before next Friday evening. As good as they are, I don't think our players can do it on their own and the more help we can get there the better."

At least the 6ft 1in Fletcher should provide the sort of aerial threat Sunderland – who have lost Darren Bent, Kenwyne Jones, Asamoah Gyan, Danny Welbeck and Nicklas Bendtner in the past two seasons – have sorely lacked.

Well aware that seven of Fletcher's 12 Premier League goals for Wolves last season were scored with his head, O'Neill – who also wants to sign a left-back before the transfer window's closure – believes he will make the most of deliveries from Stéphane Sessègnon, James McClean and Sebastian Larsson.

Moreover, Fletcher's goals per game ratio is better than one every three games; not bad for a centre-forward who has suffered two relegations from the Premier League with Burnley – who are now due a 15% cut of his transfer fee – and Wolves. O'Neill certainly trusts that life at Sunderland will prove third time lucky for the Scot.